The present invention relates to contacts for providing electrical connection to the substrate of an integrated circuit device and in particular to low resistance contacts including a metal silicide.
Integrated circuit devices formed on single crystal substrates typically require, for proper operation, that the substrate be maintained at a known constant electric potential. In order to provide for such constant electric potential, it is known to include one or more substrate contacts which provide an electrical pathway from an externally connectable pad or contact to the substrate. For many applications it is desirable that the electrical pathway have as low a resistance as possible. For example, programmable array logic devices typically require a low resistance pathway to the substrate since the process of programming the PAL injects a large quantity of current into the substrate. If this current is not removed quickly it can result in cross-talk which can prevent programming of adjacent devices in the array.
Although previous integrated circuit devices have included one or more substrate contacts, such contacts have typically been difficult to fabricate and/or have not as low an electrical resistance as desired.